I really only have 2 clients at the moment and 1 client that I did just a bit for. One of my long term clients is a bit sporadic because she's writing her grandmother's memoirs and will go a while until she gets a batch together to give me (typing/editing/proofreading/online research etc.) and she goes out of town on extended stays a couple of times a year. But, at the moment, I don't have an online presence so all of my work is local. I've never really done any local marketing research but because I live in such a small town where at least about 80% of the residence are either real estate agents or small business owners of one type or another, I know there's a need. Granted a lot of these people have the "I'll do everything myself and save money" concept in their head but I also haven't really let them know what a VA can do for them yet.
I don't know how big the area you live in is but if it's small like mine, just keep you're ear to the ground and then put yourself out there. You'll probably get a feel of who can use you just by what you see and hear. However, as far as organized market research goes, maybe you could do your own phone survey (I think you'd probably get more people to answer your questions that way. Just keep it as short and sweet as possible and know that there may be some that will help you and those that don't want to be bothered. Just move on in that case). Also, if you have a niche, maybe you could look through the phone book, online, with the Chamber of Commerce etc. to find out how many businesses fall within your niche and/or target market, how many average employees they have, their average yearly revenue (if it's available) and things like that. Businesses pay a lot of money for market research (I'm pretty sure anyhow...lol) so you may have to be a bit creative when trying to find inexpensive ways to do it on your own. Just sit down and brainstorm a few possible ideas (that's really all I was doing above) and maybe you'll come up with a few good ideas that are relatively simple to execute. Oh, and if you have any family or friends who own businesses or work for small businesses, you could ask them if they ever feel the need for extra help and, if so, what areas do they wish they had help with (not saying to drum up business or anything, just to get a feel for what the needs are). For instance, I'm a financial assistant at a small non-profit and started out as their admin assistant. Because of downsizing and such, I feel sometimes like I'm doing the work of 4 employees (my desk is always piled high) and, even though I'm the "assistant", there are many times when I really wish I could have my own assistant just to do the "everyday" things that I never seem to have the time to do (filing, data entry etc.) so that I could concentrate on the larger, more involved tasks and projects.
Sorry, this was so long. I was just trying to give you some ideas.